1. Field of the Invention
The present invention relates to a buttonhole sewing machine, and particularly to a buttonhole sewing machine which is compact in size and improved in operation, and which sews beautifully finished buttonholes with no disorder in the stitches.
2. Description of the Prior Art
The conventional buttonhole sewing technique utilizes an elongated slit s (FIG. 6a) which is terminated at its one end with an eyelet hole e, and stitches a and a' are formed in parallel at the opposite sides of the slit s and perpendicular to the slit s, the stitches a and a' being connected with each other by radial stitches b and offset stitches c and c', the eyelet hole being surrounded by these stitches c, c', and b. On the other hand, when no eyelet hole is formed, the stitches a and a' are connected through the radial stitches b (FIG. 6b), so as to provide so-called straight buttonhole sewing.
Such buttonhole sewing machines have a long history of development, and various types have been developed and disclosed, for example, in the following: